Added new fileBrowserPrivate and fileHandler extension APIs

chrome/browser/extensions/extension_file_browser_private_api.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome/browser/extensions/extension_file_browser_private_api.h"
 
+#include "base/base64.h"
+#include "base/crypto/symmetric_key.h"
+#include "base/hmac.h"
 #include "base/json/json_writer.h"
+#include "base/memory/singleton.h"
+#include "base/stringprintf.h"
 #include "base/task.h"
 #include "base/values.h"
 #include "chrome/browser/profiles/profile.h"
+#include "chrome/browser/extensions/extension_function_dispatcher.h"
+#include "chrome/browser/extensions/extension_service.h"
+#include "chrome/browser/tab_contents/context_menu_utils.h"
+#include "chrome/browser/ui/webui/extension_icon_source.h"
 #include "chrome/common/extensions/extension.h"
 #include "content/browser/browser_thread.h"
+#include "content/browser/child_process_security_policy.h"
+#include "content/browser/renderer_host/render_process_host.h"
+#include "content/browser/renderer_host/render_view_host.h"
+#include "content/browser/tab_contents/tab_contents.h"
+#include "webkit/fileapi/file_system_context.h"
 #include "webkit/fileapi/file_system_operation.h"
+#include "webkit/fileapi/file_system_path_manager.h"
 #include "webkit/fileapi/file_system_types.h"
+#include "webkit/glue/context_menu.h"
+
+#define SHA1_SIZE_IN_BITS 160
+
+const char kContextTaskIdSchema[] = "context-task";
+
+bool GetContextMenuItems(Profile* profile,
+                         const ContextMenuParams& params,
+                         ExtensionMenuItem::List* results) {
+  ExtensionService* service = profile->GetExtensionService();
+  if (!service)
+    return false;  // In unit-tests, we may not have an ExtensionService.
+
+  // Get a list of extension id's that have context menu items, and sort it by
+  // the extension's name.
+  ExtensionMenuManager* menu_manager = service->menu_manager();
+  std::set<std::string> ids = menu_manager->ExtensionIds();
+  std::vector<std::pair<std::string, std::string> > sorted_ids;
+  for (std::set<std::string>::iterator i = ids.begin(); i != ids.end(); ++i) {
+    const Extension* extension = service->GetExtensionById(*i, false);
+    if (extension)
+      sorted_ids.push_back(
+          std::pair<std::string, std::string>(extension->name(), *i));
+  }
+
+  if (sorted_ids.empty())
+    return true;
+
+  std::vector<std::pair<std::string, std::string> >::const_iterator i;
+  for (i = sorted_ids.begin(); i != sorted_ids.end(); ++i) {
+    const std::string& extension_id = i->second;
+    const Extension* extension = service->GetExtensionById(extension_id, false);
+    bool can_cross_incognito = service->CanCrossIncognito(extension);
+    const ExtensionMenuItem::List* all_items =
+        menu_manager->MenuItems(extension_id);
+    ExtensionMenuItem::List relevant_items =
+        ContextMenuUtils::GetRelevantExtensionItems(*all_items,
+                                                    params,
+                                                    profile,
+                                                    can_cross_incognito);
+    results->insert(results->end(), relevant_items.begin(),
+                    relevant_items.end());
+  }
+  return true;
+}
+
+void CreateContextMenuParams(const GURL& source_url,
+                             const std::string& file_url,
+                             ContextMenuParams* params) {
+  DCHECK(params);
+  params->is_image_blocked = false;
+  params->spellcheck_enabled = false;
+  params->is_editable = false;
+  params->media_flags = 0;
+  params->edit_flags = 0;
+  params->media_type = WebKit::WebContextMenuData::MediaTypeFile;
+  params->src_url = GURL(file_url);
+  params->page_url = source_url;
+}
+
+// Given the list of selected files, returns array of context menu tasks
+// that are sahred
+bool FindCommonTasks(Profile* profile,
+                     const GURL& source_url,
+                     ListValue* files_list,
+                     ExtensionMenuItem::List* common_tasks) {
+  common_tasks->clear();
+  for (size_t i = 0; i < files_list->GetSize(); ++i) {
+    std::string file_url;
+    if (!files_list->GetString(i, &file_url))
+      return false;
+
+    ContextMenuParams params;
+    CreateContextMenuParams(source_url, file_url, &params);
+
+    ExtensionMenuItem::List file_actions;
+    if (!GetContextMenuItems(profile, params, &file_actions))
+      return false;
+    // If there is nothing to do for one file, the intersection of tasks for all
+    // files will be empty at the end.
+    if (!file_actions.size()) {
+      common_tasks->clear();
+      return true;
+    }
+    // For the very first file, just copy elements.
+    if (i == 0) {
+      common_tasks->insert(common_tasks->begin(),
+                           file_actions.begin(),
+                           file_actions.end());
+      std::sort(common_tasks->begin(), common_tasks->end());
+    } else if (common_tasks->size()) {
+      // For all additional files, find intersection between the accumulated
+      // and file specific set.
+      std::sort(file_actions.begin(), file_actions.end());
+      ExtensionMenuItem::List intersection(common_tasks->size());
+      ExtensionMenuItem::List::iterator intersection_end =
+          std::set_intersection(common_tasks->begin(),
+                                common_tasks->end(),
+                                file_actions.begin(),
+                                file_actions.end(),
+                                intersection.begin());
+      common_tasks->clear();
+      common_tasks->insert(common_tasks->begin(),
+                           intersection.begin(),
+                           intersection_end);
+      std::sort(common_tasks->begin(), common_tasks->end());
+    }
+  }
+  return true;
+}
+
+// Breaks down task_id that is used between getFileTasks() and executeTask() on
+// its building blocks. task_id field the following structure:
+//     <task-type>:<extension-id>/<task-action-id>
+// Currently, the only supported task-type is of 'context'.
+bool CrackTaskIdentifier(const std::string& task_id,
+                         std::string* task_type,
+                         std::string* target_extension_id,
+                         std::string* action_id) {
+  std::string::size_type pos_col = task_id.find(':');
+  if (pos_col == std::string::npos)
+    return false;
+  *task_type = task_id.substr(0, pos_col);
+  std::string::size_type pos_slash = task_id.find('/');
+  if (pos_slash == std::string::npos)
+    return false;
+  *target_extension_id = task_id.substr(pos_col + 1, pos_slash - pos_col - 1);
+  *action_id = task_id.substr(pos_slash + 1);
+  return true;
+}
+
+std::string MakeTaskID(const char* task_schema,
+                       const char* extension_id,
+                       int action_id) {
+  return base::StringPrintf("%s:%s/%d", task_schema, extension_id, action_id);
+}
+
+// Generates hashes used for filesystem: urls that are sent to 3rd party
+// extension. Hashes generated from extension id and file url.
+// They are valid only during the lifetime of the browser instance.
+class FileHashGenerator {
+ public:
+  ~FileHashGenerator() {}
+  static FileHashGenerator* GetInstance() {
+    return Singleton<FileHashGenerator>::get();
+  }
+  // Generate hash for given url and extension combination.
+  std::string GenerateFileHash(const std::string& file_url,
+                               const std::string& extension_id) {
+    std::string data(file_url);
+    data = data.append(extension_id);
+    scoped_ptr<unsigned char> digest(new unsigned char[SHA1_SIZE_IN_BITS/8]);
+    if (!hmac_.Sign(data, digest.get(), SHA1_SIZE_IN_BITS/8))
+      return std::string();
+    std::string output;
+    if (!base::Base64Encode(std::string(reinterpret_cast<char*>(digest.get()),
+                                        SHA1_SIZE_IN_BITS/8),
+                            &output))
+      return std::string();
+    return output;
+  }
+
+ private:
+  friend struct DefaultSingletonTraits<FileHashGenerator>;
+
+  FileHashGenerator() : hmac_(base::HMAC::SHA1) {
+    scoped_ptr<base::SymmetricKey> sym_key(
+        base::SymmetricKey::GenerateRandomKey(base::SymmetricKey::AES,
+                                              SHA1_SIZE_IN_BITS));
+    std::string raw_key;
+    sym_key->GetRawKey(&raw_key);
+    hmac_.Init(raw_key);
+  }
+
+  base::HMAC hmac_;
+  DISALLOW_COPY_AND_ASSIGN(FileHashGenerator);
+};
 
 class LocalFileSystemCallbackDispatcher
     : public fileapi::FileSystemCallbackDispatcher {
  public:
   explicit LocalFileSystemCallbackDispatcher(
-      RequestLocalFileSystemFunction* function) : function_(function) {
+      RequestLocalFileSystemFunctionBase* function,
+      Profile* profile,
+      int child_id,
+      const GURL& source_url,
+      const std::string& file_url)
+      : function_(function),
+        profile_(profile),
+        child_id_(child_id),
+        source_url_(source_url),
+        file_url_(file_url) {
     DCHECK(function_);
   }
   // fileapi::FileSystemCallbackDispatcher overrides.
   virtual void DidSucceed() OVERRIDE {
     NOTREACHED();
   }
   virtual void DidReadMetadata(const base::PlatformFileInfo& info,
                                const FilePath& unused) OVERRIDE {
     NOTREACHED();
   }
   virtual void DidReadDirectory(
       const std::vector<base::FileUtilProxy::Entry>& entries,
       bool has_more) OVERRIDE {
     NOTREACHED();
   }
   virtual void DidWrite(int64 bytes, bool complete) OVERRIDE {
     NOTREACHED();
   }
   virtual void DidOpenFileSystem(const std::string& name,
                                  const FilePath& path) OVERRIDE {
+    DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
+    // Set up file permission access.
+    if (file_url_.length()) {
+      if (!SetupFileAccessPermissions()) {
+        DidFail(base::PLATFORM_FILE_ERROR_SECURITY);
+        return;
+      }
+    }
+
     BrowserThread::PostTask(
         BrowserThread::UI, FROM_HERE,
         NewRunnableMethod(function_,
-            &RequestLocalFileSystemFunction::RespondSuccessOnUIThread,
+            &RequestLocalFileSystemFunctionBase::RespondSuccessOnUIThread,
             name,
-            path));
+            path,
+            file_url_));
   }
   virtual void DidFail(base::PlatformFileError error_code) OVERRIDE {
     BrowserThread::PostTask(
         BrowserThread::UI, FROM_HERE,
         NewRunnableMethod(function_,
-            &RequestLocalFileSystemFunction::RespondFailedOnUIThread,
+            &RequestLocalFileSystemFunctionBase::RespondFailedOnUIThread,
             error_code));
   }
  private:
-  RequestLocalFileSystemFunction* function_;
+
+  // Checks legitimacy of file url and grants access permissions.
+  bool SetupFileAccessPermissions() {
+    GURL file_origin_url;
+    FilePath virtual_path;
+    fileapi::FileSystemType type;
+    fileapi::FileSystemPathManager* path_manager =
+        profile_->GetFileSystemContext()->path_manager();
+
+    // Check file url hash first.
+    std::string::size_type pos = file_url_.find('#');
+    if (pos == std::string::npos)
+      return false;
+    std::string url_hash = file_url_.substr(pos + 1);
+    std::string file_url = file_url_.substr(0, pos);
+    std::string extension_id = source_url_.GetOrigin().host();
+    std::string expected_hash = FileHashGenerator::GetInstance()->
+        GenerateFileHash(file_url, extension_id);
+    if (expected_hash != url_hash)
+      return false;
+
+    if (!path_manager->CrackFileSystemPath(FilePath(file_url),
+                                          &file_origin_url,
+                                          &type,
+                                          &virtual_path)) {
+      return false;
+    }
+    // Make sure this url really used by the right caller extension.
+    if (source_url_.GetOrigin() != file_origin_url) {
+      DidFail(base::PLATFORM_FILE_ERROR_SECURITY);
+      return false;
+    }
+    FilePath root_path = path_manager->GetFileSystemRootPathOnFileThread(
+        file_origin_url,
+        fileapi::kFileSystemTypeLocal,
+        FilePath(virtual_path),
+        false);     // create
+    FilePath finalFilePath = root_path.Append(virtual_path);
+    // Grant read access permission to this file.
+    ChildProcessSecurityPolicy::GetInstance()->GrantReadFile(child_id_,
+                                                             finalFilePath);
+    return true;
+  }
+
+  RequestLocalFileSystemFunctionBase* function_;
+  Profile* profile_;
+  // Renderer process id.
+  int child_id_;
+  // Extension source URL.
+  GURL source_url_;
+  std::string file_url_;
   DISALLOW_COPY_AND_ASSIGN(LocalFileSystemCallbackDispatcher);
 };
 
-RequestLocalFileSystemFunction::RequestLocalFileSystemFunction() {
-}
-
-RequestLocalFileSystemFunction::~RequestLocalFileSystemFunction() {
-}
-
-bool RequestLocalFileSystemFunction::RunImpl() {
+void RequestLocalFileSystemFunctionBase::RequestOnFileThread(
+    const GURL& source_url, const std::string& file_url) {
   fileapi::FileSystemOperation* operation =
       new fileapi::FileSystemOperation(
-          new LocalFileSystemCallbackDispatcher(this),
+          new LocalFileSystemCallbackDispatcher(
+              this,
+              profile(),
+              dispatcher()->render_view_host()->process()->id(),
+              source_url,
+              file_url),
           BrowserThread::GetMessageLoopProxyForThread(BrowserThread::FILE),
           profile()->GetFileSystemContext(),
           NULL);
-  GURL origin_url = source_url().GetOrigin();
+  GURL origin_url = source_url.GetOrigin();
   operation->OpenFileSystem(origin_url, fileapi::kFileSystemTypeLocal,
                             false);     // create
+}
+
+bool RequestLocalFileSystemFunctionBase::RunImpl() {
+  std::string file_url;
+  if (args_->GetSize())
+    args_->GetString(0, &file_url);
+  BrowserThread::PostTask(
+      BrowserThread::FILE, FROM_HERE,
+      NewRunnableMethod(this,
+          &RequestLocalFileSystemFunctionBase::RequestOnFileThread,
+          source_url_,
+          file_url));
   // Will finish asynchronously.
   return true;
 }
 
-void RequestLocalFileSystemFunction::RespondSuccessOnUIThread(
-    const std::string& name, const FilePath& path) {
+void RequestLocalFileSystemFunctionBase::RespondSuccessOnUIThread(
+    const std::string& name, const FilePath& path,
+    const std::string& file_url) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   result_.reset(new DictionaryValue());
   DictionaryValue* dict = reinterpret_cast<DictionaryValue*>(result_.get());
   dict->SetString("name", name);
   dict->SetString("path", path.value());
   dict->SetInteger("error", base::PLATFORM_FILE_OK);
+  if (file_url.size())
+    dict->SetString("fileUrl", file_url);
   SendResponse(true);
 }
 
-void RequestLocalFileSystemFunction::RespondFailedOnUIThread(
+void RequestLocalFileSystemFunctionBase::RespondFailedOnUIThread(
     base::PlatformFileError error_code) {
   DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
   result_.reset(new DictionaryValue());
   DictionaryValue* dict = reinterpret_cast<DictionaryValue*>(result_.get());
   dict->SetInteger("error", static_cast<int>(error_code));
   SendResponse(true);
 }
 
+bool GetFileTasksFileBrowserFunction::RunImpl() {
+  ListValue* files_list = NULL;
+  if (!args_->GetList(0, &files_list))
+    return false;
+
+  result_.reset(new ListValue());
+  ListValue* result_list = reinterpret_cast<ListValue*>(result_.get());
+
+  ExtensionMenuItem::List common_tasks;
+  if (!FindCommonTasks(profile_, source_url_, files_list, &common_tasks))
+    return false;
+
+  ExtensionService* service = profile_->GetExtensionService();
+  for (ExtensionMenuItem::List::iterator iter = common_tasks.begin();
+       iter != common_tasks.end();
+       ++iter) {
+    if ((*iter)->type() != ExtensionMenuItem::NORMAL)
+      continue;
+    const std::string extension_id = (*iter)->extension_id();
+    const Extension* extension = service->GetExtensionById(extension_id, false);
+    if (!extension) {
+      LOG(WARNING) << "Disabled extension" << extension_id;
+      continue;
+    }
+    DictionaryValue* task = new DictionaryValue();
+    task->SetString("taskId", MakeTaskID(kContextTaskIdSchema,
+                                         extension_id.c_str(),
+                                         (*iter)->id().uid));
+    task->SetString("title", (*iter)->title());
+    GURL icon =
+        ExtensionIconSource::GetIconURL(extension,
+                                        Extension::EXTENSION_ICON_SMALLISH,
+                                        ExtensionIconSet::MATCH_BIGGER,
+                                        false);     // grayscale
+    task->SetString("iconUrl", icon.spec());
+    result_list->Append(task);
+  }
+
+  // TODO(zelidrag, serya): Add intent content tasks to result_list once we
+  // implement that API.
+  SendResponse(true);
+  return true;
+}
+
+bool ExecuteTasksFileBrowserFunction::RunImpl() {
+  // First param is task id that was to the extension with getFileTasks call.
+  std::string task_id;
+  if (!args_->GetString(0, &task_id) || !task_id.size())
+    return false;
+
+  // The second param is the list of files that need to be executed with this
+  // task.
+  ListValue* files_list = NULL;
+  if (!args_->GetList(1, &files_list))
+    return false;
+
+  if (!files_list->GetSize())
+    return true;
+
+  std::string task_type;
+  std::string target_extension_id;
+  std::string action_id;
+  if (!CrackTaskIdentifier(task_id, &task_type, &target_extension_id,
+                           &action_id)) {
+    return false;
+  }
+
+  if (task_type == kContextTaskIdSchema) {
+    ExecuteContextMenuTasks(target_extension_id, action_id, files_list);
+  } else {
+    LOG(WARNING) << "Unsupported task type of: " << task_type;
+    // TODO(zelidrag, serya): Add intent content tasks here once we implement
+    // that API.
+    return false;
+  }
+  SendResponse(true);
+  return true;
+}
+
+std::string ExecuteTasksFileBrowserFunction::MakeSafeFileUrl(
+  const std::string& origin_file_url, const std::string& extension_id) {
+  // Replace extension part of the url with one from the target.
+  std::string::size_type pos = origin_file_url.find("/local/");
+  if (pos == std::string::npos)
+    return std::string();
+  std::string file_url = base::StringPrintf(
+      "filesystem:chrome-extension://%s/%s",
+      extension_id.c_str(),
+      origin_file_url.substr(pos + 1).c_str());
+  std::string hash =
+      FileHashGenerator::GetInstance()->GenerateFileHash(file_url,
+                                                         extension_id);
+  file_url = file_url.append("#");
+  return file_url.append(hash);
+}
+
+bool ExecuteTasksFileBrowserFunction::ExecuteContextMenuTasks(
+    const std::string& extension_id, const std::string& action_id,
+    ListValue* files_list) {
+  ExtensionMenuManager* manager =
+      profile_->GetExtensionService()->menu_manager();
+  for (size_t i = 0; i < files_list->GetSize(); i++) {
+    std::string origin_file_url;
+    if (!files_list->GetString(i, &origin_file_url)) {
+      result_.reset(new FundamentalValue(false));
+      SendResponse(true);
+      return false;
+    }
+    std::string file_url = MakeSafeFileUrl(origin_file_url, extension_id);
+    if (!file_url.size()) {
+      result_.reset(new FundamentalValue(false));
+      SendResponse(true);
+      return false;
+    }
+    ContextMenuParams params;
+    CreateContextMenuParams(source_url_, file_url, &params);
+    ExtensionMenuItem::Id menuItemId(profile_, extension_id,
+                                     atoi(action_id.c_str()));
+    manager->ExecuteCommand(profile_,
+                            NULL,     // tab_contents, not needed in args.
+                            params,
+                            menuItemId);
+  }
+  result_.reset(new FundamentalValue(true));
+  SendResponse(true);
+  return true;
+}